1. Field of the Invention
The present invention relates generally to the field of electronic filters. More specifically, the present invention relates to a system providing tunable, balanced loss compensation for an unbalanced electronic filter.
2. Description of the Related Art
In communication systems, electronic filters are used for signal processing. Electronic filters eliminate unwanted frequencies from an electronic signal. Different types of electronic filters, such as low-pass filters, band-pass filters, high-pass filters, active filters and passive filters, may be used for this purpose. An electronic filter is usually a combination of inductors and capacitors, referred to as an LC circuit. The electronic filter may include one or more LC circuits and may consist of balanced and unbalanced structures. Examples of balanced structures include balanced LC oscillators and shunt LC resonators. Examples of unbalanced structures include series LC resonators.
The inductors and capacitors in electronic filters have a resistive component that causes losses in the electronic filter during transmission. These losses result in a decrease in the quality of the frequency response provided by the electronic filter. Hence, losses in the electronic filter need to be compensated. Moreover, these losses in the electronic filter may vary with the process, temperature and other factors. Therefore, loss compensation in the electronic filter needs to be tunable, so that it may be adjusted according to the variations in the losses.
Existing methods and systems provide loss compensation for a balanced structure in an electronic filter by using a cross-coupled pair of transistors. This cross-coupled pair of transistors, referred to as a negative resistor, compensates for the resistive losses in a balanced structure. However, the cross-coupled pair of transistors, when used for loss compensation in an unbalanced structure, results in the development of even-order harmonics. These even-order harmonics are undesirable since they distort the frequency response of the electronic filter.
In light of the foregoing discussion, there exists a need for a system to provide tunable loss compensation in an electronic filter. Further, the system provides balanced loss compensation for an unbalanced structure in the electronic filter.